Switches are used in a variety of applications to control the on and off states of loads, to sense the proximity or position of input devices, to provide inputs to data processing systems, and so on. Many of these applications involve complex systems, such as those used on aircraft or oil wells, which rely on a large number of switches. Many of these switches experience intensive use in these systems and, as a result, fail because their parts simply wear out. Switches can also fail because they are driven or otherwise travel out of range.
Many of the switches used in complex systems provide critical functions. When a switch that provides a critical function fails, the failure can result in a potentially dangerous and/or economically costly condition. Therefore, when such a switch fails, it is important to replace it as soon as possible in order to avoid or minimize the potentially dangerous and/or economically costly condition. However, when a switch fails in a complex system, it can be very difficult to locate it so that it can be replaced.
The switch of the present invention is a non-contact position sensor with a built in self-diagnostic system. The self diagnostic system can indicate that the switch travel out of range and/or that the switch is not functioning properly. This switch has less wear because it does not contact the object that it is sensing, and there is less chance that this switch will travel out of range. Therefore, the switch of the present invention has a longer life. Also, this switch detects when it has failed so that it can be easily located and replaced.